There have been many studies linking obesity to the development of Type 2 Diabetes Mellitus. In obesity, a chronic low-grade state of inflammation characterizes the adipose tissue as a result of macrophage infiltration and increased inflammatory cytokine production. This increased macrophage presence has been linked to the development of diabetes and reducing the number of adipose tissue macrophages has also been shown to improve insulin signaling. Osteopontin (OPN) is a glycophosphoprotein that is highly expressed in obese insulin resistant patients and rodents, particularly by macrophages in the adipose tissue. OPN also has chemoattractant properties and acts as a macrophage activator. The goal of this proposal is to target OPN specifically in adipose tissue macrophages, and thus lower the number of macrophages while also effectively reducing inflammation. Studies that involve inhibiting OPN and knockout mice all show an improvement in diet induced insulin resistance. Therefore I hypothesize that by using RNAi to knock down osteopontin in macrophages, I will reduce macrophage infiltration and inflammation, and also improve adipose tissue and liver function.